How strict are the RSS import rules?

I'd like to set up a Tumblr that grabs my Twitter feeds, and the feeds of everybody I follow, so that people can see the whole conversation.

I have figured out technically how to do this (by putting my user name and password into the Twitter feed URL), but one of the Terms and Conditions is that I must important content I created myself. If all I'm importing is the text of my friend's tweets, will this be OK or am I breaking the rules?

And if I am breaking the rules, will only this new Tumblr be shut down, or all of the ones I have created?

Thanks